The body does not lie. So stated William Moulton Marston, a psychology professor who devised components for the polygraph and in 1938 published The Lie Detector Test. Marston and his co-inventors maintained that regardless of how well a person could control his voice and face, other signs such as blood pressure, heart rate, respiration and skin conductivity would betray him when he told a lie. The physiological changes, they said, were triggered by the anxiety an individual feels when he knows he is fabricating information. Marstons own work with the machine convinced him that women were more trustworthy than men, and he went on to champion the females role in society, in part by creating and writing the comic strip "Wonder Woman" (who wielded a "truth lasso," among other gadgets).

The trouble with the polygraph, scientists found later, was that a person could become anxious simply by being hooked up to the machine and even more so when asked probing questions. After years of controversy, evidence gleaned from lie detectors remains inadmissible in most courtrooms.